Failure diagnosis in rotating machines using fra involving the rotation angle of the rotor

Several studies have shown, that the SFRA method is not only suitable for transformers but also for rotating machines as a tool for reliable condition diagnosis. Is has the ability to sensitively detect diverse faults, which influence the frequency response in different frequency ranges. Therefore, a condition assessment of a machine is possible. Even faults that are not directly in the electrical measuring circuit of the SFRA have an effect on the frequency response and are therefore detectable. Examples are rod ruptures in the damper cage of synchronous machines or broken rods in squirrel cages of induction machines. Conventional methods are often unable to detect this types of fault, and new, alternative methods are also often very complex and in some cases not practical. This paper focuses on the SFRA method for the detection of different failure modes involving the rotation angle of the rotor. The rotor position is altered, allowing the detection of failures without comparison to a fingerprint. This is a general and transferable approach, which might provide new possibilities for failure diagnosis in rotating machines, even if no previous SFRA measurement is available.